Direct Evidence of Electron Accumulation in the Grain Boundary of Yttria-Doped Nanocrystalline Zirconia Ceramics

2006 ◽  
Vol 9 (8) ◽  
pp. J34 ◽  
Author(s):  
Jong Soo Lee ◽  
Umberto Anselmi-Tamburini ◽  
Zuhair A. Munir ◽  
Sangtae Kim
Keyword(s):  
Grain Boundary ◽  
Direct Evidence ◽  
Zirconia Ceramics ◽  
Electron Accumulation ◽  
Nanocrystalline Zirconia

Direct evidence for grain-boundary depletion in polycrystalline CdTe from nanoscale-resolved measurements

2003 ◽  
Vol 82 (4) ◽  
pp. 556-558 ◽  
Author(s):  
Iris Visoly-Fisher ◽  
Sidney R. Cohen ◽  
David Cahen
Keyword(s):  
Grain Boundary ◽  
Direct Evidence

The Grain Boundary Diffusion Kinetics in Nanocrystalline Zirconia

1996 ◽  
Vol 458 ◽  
Author(s):  
A. P. Zhilyaev ◽  
V. Y. Gertsman ◽  
J. A. Szpunar
Keyword(s):  
Grain Boundary ◽  
Oxidation Rate ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Grain Boundary Character Distribution ◽  
Grain Boundary Character ◽  
Character Distribution ◽  
Different Types ◽  
Nanocrystalline Zirconia ◽  
Boundary Character Distribution

ABSTRACTIt is expected that the grain boundary diffusion is the principal contributor to the transport properties of nanocrystalline zirconia, and that it controls the oxidation kinetics and hydrogen permeation. This process depends on the grain boundary character distribution (i.e. the fractions of different grain boundary types) and on the topological characteristics of the grain boundary network. Modeling of the random walk problem on a planar honeycomb network for different types of the grain boundary misorientation distributions (GBMD) in nanocrystalline zirconia film is presented in the current paper. The GBMD was calculated using the model texture. Changes of the oxidation rate for different types of the grain boundary character distribution and different ratios of the bulk and grain boundary diffusion coefficients are analyzed. In this study it was found that an increase of the frequency of low energy boundaries lowers the oxidation rate.

X-Ray Reflectivity Study of Single- and Bicrystals of Gold

1990 ◽  
Vol 208 ◽  
Author(s):  
M. R. Fitzsimmons ◽  
E. Burkel ◽  
J. Peisl
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Diffuse Scattering ◽  
Direct Evidence ◽  
X Ray ◽  
Specular Reflectivity ◽  
Boundary Measurements

ABSTRACTX-ray reflectivity techniques have been used to characterize the surfaces of 0.4µm thick Au films epitaxially grown on single-crystals of NaCl. Measurements of both the specular and non-specular reflectivity suggest that the Au surface is very rough. The nonspecular reflectivity provides valuable information about the correlation of the heights at different points on the surface. The first in situ reflectivity study of the formation and destruction of a grain boundary shows direct evidence for the existence of diffuse scattering from the grain boundary. Measurements of several [0011 twist grain boundaries suggest that the roughness and texture of an interface depends upon the geometrical orientation of the surrounding substrates.

Evolution of Grain Boundary Texture in Zirconium Alloys

2011 ◽  
Vol 702-703 ◽  
pp. 710-713
Author(s):  
Karri V. Mani Krishna ◽  
Sudipto Mandal ◽  
Ankur Agrawal ◽  
Vijay Hiwarkar ◽  
Dinesh Srivastava ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Grain Boundary ◽  
Annealing Time ◽  
Considerable Increase ◽  
Direct Evidence ◽  
Texture Evolution ◽  
Zirconium Alloys ◽  
Alpha Phase ◽  
Variant Selection ◽  
Alpha Beta

Grain boundary texture evolution in case of two of the Zr based alloys (Zircaloy-4 and Zr-2.5\%Nb) was studied. In case of Zircaloy-4, grain boundary texture evolution during $\beta$ $\to$ $\alpha$ phase transformation was monitored. Direct evidence of variant selection during this transformation is presented. In case of Zr-2.5\%Nb alloy, considerable increase in $\alpha/\beta$ interfaces following Burger's orientation relationship was noticed with increasing annealing time at 700 \textdegree{}C.

Cluster ‘Contact Epitaxy’- Direct Evidence for Novel Particle: Substrate Interactions

1999 ◽  
Vol 570 ◽  
Author(s):  
M. Yeadon ◽  
J.C. Yang ◽  
M. Ghaly ◽  
R.S. Averback ◽  
J.M. Gibson
Keyword(s):  
Molecular Dynamics ◽  
Melting Point ◽  
Grain Boundary ◽  
Ag Nanoparticles ◽  
Direct Evidence ◽  
Low Energy ◽  
Novel Interactions ◽  
Ag Cluster ◽  
Dynamics Simulations ◽  
Ordered Layers

ABSTRACTIn this paper we describe observations of novel interactions between clusters of Ag deposited on the clean (001) Cu surface. The experiments are analogous to those performed by Gleiter and co-workers in the 1970's, where grain boundary orientations in particles of Cu and Ag supported on single crystal metal substrates were studied. Upon annealing close to the melting point, these particles (∼10–100μm in diameter) were found to rotate on the surface, forming low-energy grain boundary configurations with the substrate. The particles studied in our experiments are ∼104 times smaller, and show rather different behavior. In the case of Ag nanoparticles we have observed a novel phenomenon, which we call ‘contact epitaxy’, involving the formation of several monolayers of epitaxially oriented Ag at the Cu surface upon contact between this surface and the Ag cluster. The phenomenon may be understood from molecular dynamics simulations of the ‘soft impact’ between the nanoparticle and surface, which indicate that the ordered layers form within picoseconds of contact. We will discuss the mechanisms by which ‘contact epitaxy’ is believed to occur.

Direct Evidence of Dopant-Enhanced Grain-Boundary Sliding in Yttria-Stabilized Zirconia Bicrystals

2005 ◽  
Vol 88 (4) ◽  
pp. 938-942 ◽  
Author(s):  
Atsutomo Nakamura ◽  
Naoya Shibata ◽  
Nobusato Morishige ◽  
Katsuyuki Matsunaga ◽  
Yuichi Ikuhara ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Direct Evidence ◽  
Grain Boundary Sliding ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Boundary Sliding

Analytical TEM of grain boundary phases in yttria-zirconia ceramics

1987 ◽  
Vol 45 ◽  
pp. 166-167
Author(s):  
M.L. Mecartney ◽  
P. Angelini
Keyword(s):  
Grain Boundary ◽  
Tetragonal Zirconia ◽  
Ceramic Materials ◽  
Liquid Phase Sintering ◽  
Raw Material ◽  
Aluminosilicate Glass ◽  
Microstructural Development ◽  
Ionic Conductors ◽  
Zirconia Ceramics ◽  
Amorphous Silicate

Yttria-zirconia ceramics have a broad range of applications, from use as structural materials (tetragonal zirconia) to ionic conductors (cubic zirconia). Similar to many ceramic materials, these zirconia ceramics often contain small amounts of amorphous silicate phases at grain boundaries and multiple grain junctions. These phases are a result of impurities, introduced during processing or from the original raw material, or are deliberate additions to aid in the densification via liquid phase sintering. Despite the universality of these grain boundary phases, as of yet little work has been undertaken to understand their effect on the microstructural development, chemistry, and physical properties of the materials. We report here our results on analyzing a series of yttria doped zirconia ceramics to which deliberate additions of various glass phases have been added.Samples were fabricated from zirconia powders which contained 3 mol% yttria and 8 mol% yttria. Aluminosilicate glass or borosilicate glass (5 wt%) was added to the powders before sintering. The samples were hot-isostatically pressed at 1650°C for 1-100 minutes.

The Control of Grain Boundary Phases in Zirconia Ceramics

1991 ◽  
Vol 53-55 ◽  
pp. 726-731 ◽  
Author(s):  
John Drennan ◽  
R.H.J. Hannink
Keyword(s):  
Grain Boundary ◽  
Zirconia Ceramics
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